Interferon has many clinical benefits. For example, interferon is known to up-regulate the immune system. It thus is potentially useful for recruiting the patient's innate immune system to identify and attack cancer cells. Interferon's efficacy as an anti-cancer agent, however, has to date proven wanting. This has been puzzling.
For example, the most effective bladder cancer treatment currently approved in The United States is intra-urethral Bacillus Calmette-Guérin vaccine. The antigenic vaccine is thought to stimulate bladder cells to express interferon, which in turn recruits the patient's innate immune system to better recognize cancer cell surface antigens and attack cancer cells. In over a third of cases, however, the vaccine is ineffective.
Similarly, intravesical instillation of exogenously manufactured interferon polypeptide has been tested to treat bladder cancer, but has been found less effective than expected.
I have discovered why, and figured out how to fix it.